Automatic screw-threading machine



Nov. 3, 1925- A. A. SHAFER AUTOMATIC SCREW THREADING MACHINE Filed June 30, 1925 4 Sheets'-Sheet l m 2 A m 0 6 u e E m S x 4 a T1 nuw m 3 R m w E M 1 L W m O H m s v S W m 8H 1 n w. :5 A m J i m flmwfifig 8 6 w a I K TL 5 P v s i I A c u lfl gw k gm k Q m H F Ivor x M m IEIEIin m o O R m N A Av Q 0 R .0 QRNWN HQ \INJ b .mrH man Nov. 3, 1925.

Nov. 3, 1925- ,560, 87.

A. A. SHAFER AUTOMATIC SCREW THREADING MACHINE Filed June 30, 1923 4 Sheets-Sheet f Patented Nov. 3, 1925. I

UNITED STATES PATENT OFFICE.

ARTHUR A. SHAFER, F ERIE, PENNSYLVANIA, ASSIGNOR T0 RICKER'I SHAFER COM- PANY, OF ERIE, PENNSYLVANIA, A. CORPORATION OF PENNSYLVANIA.

AUTOMATIC SGREW-THREADING MACHINE.

Application filed June 30, 1923. Serial No. 648,725.

To all whom it may concern: Figure 7 shows the Worm shaft partly in Be it known that I, ARTHUR A. SHAFER, central section, showing the safety clutch a citizen of the United States, residing at mechanism.

Erie, in the county of Erie and. State of Figure 8 is a plan View of the turret 6 Pennsylvania, have invented certain new mechamsm equipped for threading sparkand useful Improvements in Automatic plugs and other similar cylindrical objects. Screw-Threading Machines; and I do here Figure 9 is a transverse vertical central by declare the following to be a full, clear, sectionof the same. and exact description of the invention, such Figure 10 is a vertical central section of as will enable others skilled in the art to a fragment of the same enlarged, showing which it appertains to make and usethe a spark-plug body in position thereon. same, reference being had to the accom- Figure l 1 is a side elevation of one of panying drawings, and to the letters of refthe supporting work holding parts mounted erence marked thereon, forming part of this in the turret shown in Fig. 8, on an enspecification. larged s I This invention relates to automatic screw Flgure 12 is a transverse section of the threading machines of the type wherein same on the line 12 in Fig. 11. work pieces are successively presented to the In these drawings A indicates the base threading die, and after being threaded are frame of the machine, upon which a dripdropped into a receptacle, said operation bepan A Is placed. Under this drip-pan is ing repeated as long as is desired. suspended a tank A, see Fig. 3, which is The object of this invention is to conprovided with a transverse division wall a struct mechanism adapted to support the the upper edge of which is somewhat lower work piece on the axial line of the threadthan the side walls of the tank A In the 25 ing die, and means to impart to the threadbottom of the drip-pan A is inserted a ing, die both rotary and longitudinal recipscreen plate a, which is providedwith openrocal movement, the rotary movement being ings over said tank A so that oil or other continuous, and the longitudinal reciprocalubricant which flows through said opentions being timed with relation to the adings will drop into said tank A at one side vancing of the die holder during the cutof the division wall a and when that side ting of threads on the work piece and reof the tank fills to the top of said division cession of the same after the threading op-' wall the oil will flow over the top of the oration. division wall a into the opposite end of The features of this invention are herethe tank A from which it can be pumped 35 inafterfully described and pointed out and by the circulating pump, as hereinafter deare illustrated in the accompanying drawscribed. The division wall a thus forms a ings, in which: settling basin wherein metal cuttings which Figure 1 is a rear end elevation of a pass through the screen a will settle to the threading machine embodying this invenbottom and only clear oil will flow over 40 tion. v r the division wall, so that the pumpmecha- Figure 2 is a plan view of the same. nism will not become clogged thereby.

Figure 3 is a vertical central section of \Vithin the drip-pan A is placed the mathe machine showing parts thereof in elevachine frame 13, in which is mountedthe tion. operating mechanism hereinafter described.

45 Figure 4 is a front end elevation showing C, indicates the spindle mechanismof the the front wall of one of the gear cases broken machine, which is shown in longitudinal secawa tion in Fig. 5. This mechanism is mounted Figure 5 is a plan view of'the gear mechain anti-friction bearings C in the frame B o nism removed from the frame of the maof the machine. 5

chine, and showing the main spindle mecha In Fig. 5, C indicates the outside spindle 'nism in horizontal longitudinal section. sleeve shaft which is mounted in the anti- Figure 6 is a vertical longitudinal secfrictionbearings hereinbefore referred to, tion of the gear case enclosing the worm and is provided at one end with a worm gearand clutch mechanism of this machine. thread ethereon. Upon the sleeve shaft C is placed a driving sprocket wheel C from which a chain belt C extends upwardly, see Fig. 3, to a suitable pulley on the shaft (not shown) of the motor C secured upon a bracket upon the upper portion ofthe ma chine frame B. Upon the sleeve shaft C, another sprocket wheel C is placed from which a chain belt 0 extends to a pulley upon the shaft of a pump mechanism 0 of ordinary construction from which a suction pipe extends into the oil tank A for the purpose hereinafter described.

Referring again to Figure 3, D indicates a hollow sleeve slidably mounted within the sleeve shaft C, and is made to revolve therewith by reason of the key cl which operates in a key-way d cutin the exterior surface of the sleeve D. This sleeve D is provided with screwthreads (Z on one end thereof. A key-way d is also out in this sleeve D across the threads (1 Upon these threads d a jam nut E is placed, and then-a flanged cylinder E, is slid over the threads d against the jam nut E, said cylinder being provided with an internal key way to receive a key E so that the cylinder E will revolve with the sleeve D. Mounted on this flanged cylinder E are a pair of cross-arms F which terminate in sliding sleeves F through which supporting slide way rods F pass, the ends thereof being supported in the frame Band bracket B, see Figs. 1 and 2, so that said flanged cylinder E will revolve within said cross arms. Abutting against the hub of the cross arms F and against the annular edge of the flanged cylinder E is a ring washer e which also is provided with a key way to receive the key E to cause it to revolve with the flanged cylinder E, and upon the threads (1 a nut E is placed which firmly clamps the enclosed mechanism against the jam nut E. It will be evident from the drawing of Fig. 5, and the foregoing description that the cross arms F can be located at, such point upon the sleeve D, within the limits of the threads (1 thereon, as may be desired.

The function of the cross-arms and sleeves FF is to support the rear end of the sleeve D and carry the roller m, see Figs. 1

and 3, 'so that it will engage the cam-slot in the drum Mflby means of which the spindle Dis given its longitudinal movement, the cross arms and sleeves FF holding the roller m rigidly, against the rotation of said drum.

Within the opposite end of the sleeve D is placed the shank of a threading die holder H, and a key bl is provided to cause said die holder to rotate with said sleeve. The die holder H is of the automatic self closing and opening type, and is fully illustrated and described in U. S. atent issued upon the application of Rudolp A. Boeh1n,December 1, 1914, No 1,119,676, in which when the forward movement of the die holder is arrested, the continued rotation of the chasers upon the threads out upon the work piece causes the chasers to spring open free from the work piece, and when the die holder is nal opening tlierethrough, in which internal threads h are cut, to receive threads on the end of a tube J which is inserted in the sleeve D, and is provided with a head J which abuts against the end of the sleeve D, so that when the tube J is screwed into the shank H of the die holder H it is drawn firmly into the sleeve D.

F rom; the pump: mechanism 0 an oil supply pipe 0 leads into the tube J so that oil therefrom will flow through the shank H into the die holder H.

Across the rear end of the machine a transverse shaft K is mounted in suitable bearings K secured to the frame B of the machine, upon which a worm gear wheel K? tions, one portion having annular angular. teeth lo cut therein, and the other portion thereof has central opening k therethrough in which a sliding rod is is placed having theeron a cylindrical body K, which likewise is provided with annular an lar teeth 10 whichengage the teeth In on t e portion K of the shaft. The part K is provided with a square shoulder which slidably enters square notches K in the portion of the shaft upon which the worm gear wheel K is secured. Upon the rod k a spring 7: is placed which is secured by means of a threaded bushing K, so that the spring k presses the toothed part k firmly against the teeth In on theportion of the shaft K, so that under ordinary load the worm gear wheel K will rotate the shaft K but an excessive load thereon will cause the teeth k and 1: to slip, thereby causing a chattering noise to give an alarm.

The sliding rod 11 is provided with a flat head, L, with which an operating lever L engages, so that the clutch can be opened,

when desired, and the train of gears, hereinafter described, operated thereby, stopped.

parts of this safety clutch are maintained in alignment by means of the bearing K.

Upon the shaft K is placed a worm wheel M, and a spiral gear wheel N, see. Figs. 1, 2 and 6,

Upon a shaft M on the frame'B of the machine, is a worm gear wheel M which intermeshes with the worm wheel M, and upon the shaft M is secured a drum having a cam slot M cut in the periphery thereof, in which a roller m upon a stud post projecting from the hub of the cross arms F operates, and by which the sleeve D in the spindle sleeve shaft C is caused to reciprocate longitudinally .as it rot-ates. The angular courses of this cam slot M are arranged to coincide with the pitch of the thread being cut by the threading die H, and with the desired speed of advancing toward the work piece, and receding therefrom.

Mounted in suitable bearings there is a shaft N upon which a spiral gear wheel N is secured, see Figs. 1, 2 and 5, which gear wheel intermeshes with the spiral gear wheel The shaft N extends forward to the front end of the machine where it connects with the turret operating gear, as hereinafter described.

' On the front end of the machine frame B is placed a rotatable turret mechanism, P, which is longitudinally adjustable thereon, by means of an adjusting screw 7) in the usual manner, and is clamped in place by means of a central bolt 39, see Figs. 2, 3 and 9. This turret mechanism consists of a base P which rests upon the frame 13. and is providedwith' a pivot post P upon which the revolving ring P, turns, secured to the under side of the turret ring P, is a gear wheel P of the type known as a Geneva wheel, see Fig. 5, which is provided with spaced notches 79 to receive the single cog p on the rotating disc p. The disc P is secured upon a vertical shaft 79 which extends through a gear case P secured to the base J? of the turret mechanism.

Within this gear case there is secured upon the shaft p a spiral gear wheel 72 which intermeshes with the spiral gear 'wheel Q, secured upon a sleeve shaft Q which is journaled in the gear case P This sleeve shaft Q is connected with the shaft- N, see Figs. 2 and 5 by means of a sliding connection as indicated by broken lines in Fig. 5. The shaft N has a constant rotative motion imparted to it by the shaft K which causes the disc P to rotate in the direction of the arrow, and at each revolution thereof the cog p engages a notch p in-the Geneva wheel P and .causes it and the turret ring P to revolve in the direction of the arrow 'thereon,'one space. The edge of the Geneva WlIGGIP between the notches p is formed to fit curved perimeter of the disc P, so that when the cog p leaves a notch p in the mounted longitudinally wheel P, the wheel is held stationary by the disc P until the cog p enga es the next notch, thus imparting a stepy-step rotation of the turret.

In the edge of the turretring P are provided rectangular recesses R which are lined with hardened metal U-shaped plates 1', see Figs. 8, 9 and 10, and centrally in each recess is placed a mandrel R adapted to support a hollow work piece, such as a spark-plug body R see Fig. 10, so that the hexagon portion thereof will engage the walls of the rectangular recesses to prevent the work piece from turning on the mandrel B. On top of the turret ring P is placed a plate S which is retained by a nut s, and prevented from rotating by means of screw 8' which passes therethrough and into the post P Secured on the plate S there is an arm S which projects over the work piece, R the edge 8 thereof beingturned down in front of the hexagonal portion of the work piece, and adapted to prevent the same from being drawn off of the mandrel during the threading process, as hereinafter described. There is also provided another arm S which is secured upon the plate S, which engages the rear surface of the work piece when the turret carries it forward after the threading process, and causes it to slide off of the mandrel.

lVhile the turret mechanism is shown as being adapted to hold spark-plug bodies for threading it will be evident that it can be adapted for holding other articles desired to be threaded without material change in the principle of operation.

In Figs. 2, 3, and 5 the threading die holder H is shown as provided with'adie closing flange k which, when the die holder is caused to recede from the work, engages a roller h in the frame of the machine, see Fig. 3, which causes the closing mechanism -in"'the die holder to operate to close the chaser, (not shown) ready for the next out.

In operation the machine is started causing the die holder to rotate; the worm threads on the sleeve shaft C through its associated train of gears causes the 'cam drum to rotate in timed relation to the predetermined pitch of the thread to be cut by the die holder, and the cam slot M in said drum causes the die sleeve D to move longitudinally to carry the die holder H toward the turret P, and also causes the shaft N to rotate the disc P, which through the Geneva gear causes the turret mechanism to revolve step-by-step in-relation to the number of revolutions necessary for the die holder to cut the desired-number of threads.

The operator then places upon the mandrel the work piece for which the turret is designed. When the die holder has completed the threads on a work piece the cam slot M in the drum causes the die holder to commence its recession from the turret thereby causing the work piece R to engage the down turned edge e of the arm S which prevents the work piece from being drawn off of the mandrel R thus placing a strain on the chasers in the die holder and causing the dies to open free of the cut threads. The die holder continues its recession until the closing flange h thereon engages the roller [L3 on the body of the machine which again closes the chasers. During the recesssion and closing of the die holder the Geneva gear of the turret causes the next work piece thereon to be swung into threading position, and the operation is repeated, During the operation of the machine, as long as the die holder H rotates, a stream of oil is caused to flow through the spindle mechanism and die, which drips into the pan A, and thence into the tank A as described. Should, by accident, the revolution of the turret P be stopped by any reason, thesafety clutch mechanism in the shaft K will slip, thereby.

causing an alarm when the lever L'- can be operated to open the clutch, so that there will be no strain on the turret revolving mechanism or the mechanism which causes the diev holder H to reciprocate, until the cause of the trouble is removed.

Having thus fully described this invention so that others canutilize the same, it

is not desired to be limited to the exact mechanism shown and described. as many modifications can be made therein without departing from-the scope of the. invention,

therefore what is claimed as new and is desired to secure by Letters Patent is: 1. Ina machine of the class described, a hollow sleeve shaft, means to cause the same to rotate, worm threads on said sleeve shaft, a hollow shaft within said sleeve shaft, adapted to receive the shank of a threading die holder in one end thereof, key and key way mechanism adapted to permit the hollow shaft to move longitudinally within said sleeve shaft while being revolved thereby, gear'mechanism *adapted to be actuated by said worm threads to cause said hollow shaft to reciprocate, and means to present a succession of Work pieces to said threading die. 2. In a machine of the class described, a hollow shaft, a threading die holder, a shank thereon inserted into said shaft, threads on the opposite end of said hollow shaft, a jam nut thereon, a flanged cylinder slidable over said threads and abutting against said nut, key and key-way mechanism to cause said cylinder to rotate with washer abutting against the annular edge of said cylinder and said key, and a clamp ing nut engaging the threads on said shaft adapted to clamp said parts against said jam nut.

3. In a machine of the class described, a hollow sleeve shaft, means to rotate said shaft, a shaft slidable within said sleeve shaft having a longitudinal opening in one end thereof, a threading die holder, a shank thereon adapted to be secured in said opening, means to cause said shaft to rotate in unison with said sleeve shaft, horizontal slide mechanism rotatably secured on said. shaft, cam mechanism adapted to engage said slide mechanism to cause said shaft to move longitudinally in said sleeve shaft,

and gear and shaft mechanism adapted to rotate said cam mechanism in timed relation to the rotation o'f said sleeve shaft.

4. In a machine of the class described, a frame, a turret base secured on said frame, a turret ring pivoted on said base and having radial recesses in the periphery thereof, radial mandrels in said recesses, a non-rotatable plate secured over said ring, an arm secured on said plate and extending over the edge of said ring at one point and adapt ed to retain a work piece on the mandrel under said arm, and gear mechanism to rotate said ring step-by-step.

In a machine of the class described, a frame, a shaft rotatable and slidably mounted therein, a threading die holder secured on said shaft, worm threads on said shaft, a transverse shaft mounted on said frame, a gear wheel on'said shaft meshing with said worm threads, cam mechanism, gear mechanism to operate said cam mechanism, slide rods secured in said frame parallel with said slidably mounted rotatable shaft, cross arm mechanism slidably mounted on said slide rods and rotatably and non-slidably secured on said slidable and rotatable shaft, means on said cross arm mechanism to engage said cam mechanism whereby said slidable and rotatable shaft is caused to reciprocate longitudinally, a rotatable work holder, gear mechanism to cause the same to rotate step-by-step, and shaft and gear mechanism actuated by said transverse shaft to actuate said work holder gear.

In testimony whereof I afiix my signature.

ARTHUR A. SHAFER. 

